The article investigates the emotional practices among radical Pietists during their conversion from "false" to "true" Christianity. It argues that melancholy and anxiety were considered necessary and edifying feelings during this process. Through bodily practices, the convert demonstrated that he or she was in a state of affect: a medium for the works of God. Among the wider population in Denmark-Norway, however, the distinction between true and false Christians, employed by both moderate and radical Pietists, caused despair. This article discusses the influence of Pietism on modern emotional categories, and demonstrates how Pietists both relied on old understandings of emotions and created new ones.